[dpdk-dev] [PATCH v5 19/19] timer: add support to non-EAL thread

Liang, Cunming cunming.liang at intel.com
Fri Feb 13 01:55:32 CET 2015



> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Thursday, February 12, 2015 9:54 PM
> To: Liang, Cunming; dev at dpdk.org
> Cc: olivier.matz at 6wind.com
> Subject: RE: [PATCH v5 19/19] timer: add support to non-EAL thread
> 
> Hi lads,
> 
> > -----Original Message-----
> > From: Liang, Cunming
> > Sent: Thursday, February 12, 2015 8:17 AM
> > To: dev at dpdk.org
> > Cc: Ananyev, Konstantin; olivier.matz at 6wind.com; Liang, Cunming
> > Subject: [PATCH v5 19/19] timer: add support to non-EAL thread
> >
> > Allow to setup timers only for EAL (lcore) threads (__lcore_id <
> MAX_LCORE_ID).
> > E.g. – dynamically created thread will be able to reset/stop timer for lcore
> thread,
> > but it will be not allowed to setup timer for itself or another non-lcore thread.
> > rte_timer_manage() for non-lcore thread would simply do nothing and return
> straightway.
> >
> > Signed-off-by: Cunming Liang <cunming.liang at intel.com>
> > ---
> >  v5 changes:
> >    add assert in rte_timer_manage
> >    remove duplicate check in timer_set_config_state
> >
> >  lib/librte_timer/rte_timer.c | 31 ++++++++++++++++++++++---------
> >  lib/librte_timer/rte_timer.h |  4 ++--
> >  2 files changed, 24 insertions(+), 11 deletions(-)
> >
> > diff --git a/lib/librte_timer/rte_timer.c b/lib/librte_timer/rte_timer.c
> > index 269a992..fa43fa9 100644
> > --- a/lib/librte_timer/rte_timer.c
> > +++ b/lib/librte_timer/rte_timer.c
> > @@ -35,6 +35,7 @@
> >  #include <stdio.h>
> >  #include <stdint.h>
> >  #include <inttypes.h>
> > +#include <assert.h>
> >
> >  #include <rte_atomic.h>
> >  #include <rte_common.h>
> > @@ -79,9 +80,10 @@ static struct priv_timer priv_timer[RTE_MAX_LCORE];
> >
> >  /* when debug is enabled, store some statistics */
> >  #ifdef RTE_LIBRTE_TIMER_DEBUG
> > -#define __TIMER_STAT_ADD(name, n) do {				\
> > -		unsigned __lcore_id = rte_lcore_id();		\
> > -		priv_timer[__lcore_id].stats.name += (n);	\
> > +#define __TIMER_STAT_ADD(name, n) do {					\
> > +		unsigned __lcore_id = rte_lcore_id();			\
> > +		if (__lcore_id < RTE_MAX_LCORE)				\
> > +			priv_timer[__lcore_id].stats.name += (n);	\
> >  	} while(0)
> >  #else
> >  #define __TIMER_STAT_ADD(name, n) do {} while(0)
> > @@ -135,7 +137,7 @@ timer_set_config_state(struct rte_timer *tim,
> >
> >  		/* timer is running on another core, exit */
> >  		if (prev_status.state == RTE_TIMER_RUNNING &&
> > -		    (unsigned)prev_status.owner != lcore_id)
> > +		    prev_status.owner != (uint16_t)lcore_id)
> >  			return -1;
> >
> >  		/* timer is being configured on another core */
> > @@ -366,9 +368,15 @@ __rte_timer_reset(struct rte_timer *tim, uint64_t
> expire,
> >
> >  	/* round robin for tim_lcore */
> >  	if (tim_lcore == (unsigned)LCORE_ID_ANY) {
> > -		tim_lcore = rte_get_next_lcore(priv_timer[lcore_id].prev_lcore,
> > -					       0, 1);
> > -		priv_timer[lcore_id].prev_lcore = tim_lcore;
> > +		if (lcore_id != LCORE_ID_ANY) {
> > +			tim_lcore = rte_get_next_lcore(
> > +				priv_timer[lcore_id].prev_lcore,
> > +				0, 1);
> > +			priv_timer[lcore_id].prev_lcore = tim_lcore;
> > +		} else
> > +			/* non-EAL thread do not run rte_timer_manage(),
> > +			 * so schedule the timer on the first enabled lcore. */
> > +			tim_lcore = rte_get_next_lcore(LCORE_ID_ANY, 0, 1);
> >  	}
> >
> >  	/* wait that the timer is in correct status before update,
> > @@ -378,7 +386,8 @@ __rte_timer_reset(struct rte_timer *tim, uint64_t
> expire,
> >  		return -1;
> >
> >  	__TIMER_STAT_ADD(reset, 1);
> > -	if (prev_status.state == RTE_TIMER_RUNNING) {
> > +	if (prev_status.state == RTE_TIMER_RUNNING &&
> > +	    lcore_id != LCORE_ID_ANY) {
> >  		priv_timer[lcore_id].updated = 1;
> >  	}
> >
> > @@ -455,7 +464,8 @@ rte_timer_stop(struct rte_timer *tim)
> >  		return -1;
> >
> >  	__TIMER_STAT_ADD(stop, 1);
> > -	if (prev_status.state == RTE_TIMER_RUNNING) {
> > +	if (prev_status.state == RTE_TIMER_RUNNING &&
> > +	    lcore_id != LCORE_ID_ANY) {
> >  		priv_timer[lcore_id].updated = 1;
> >  	}
> 
> About ' lcore_id != LCORE_ID_ANY' vs ' lcore_id < RTE_MAX_LCORE'.
> I think both ways are valid right now.
> Though using ' lcore_id != LCORE_ID_ANY' means, that if user will setup
> PER_LCORE(_lcore_id) for dynamically created thread to some value >=
> RTE_MAX_LCORE,
> then our code will not work properly.
> Konstantin
[LCM] Ok, now we get the agreement as below.
1. only using '< RTE_MAX_LCORE' to check the EAL thread with valid lcore_id.
2. LCORE_ID_ANY is used as lcore_id default value or used for any  unspecified lcore_id assignment.
> 
> >
> > @@ -499,6 +509,9 @@ void rte_timer_manage(void)
> >  	uint64_t cur_time;
> >  	int i, ret;
> >
> > +	/* timer manager only runs on EAL thread */
> > +	assert(lcore_id != LCORE_ID_ANY);
> > +
> >  	__TIMER_STAT_ADD(manage, 1);
> >  	/* optimize for the case where per-cpu list is empty */
> >  	if (priv_timer[lcore_id].pending_head.sl_next[0] == NULL)
> > diff --git a/lib/librte_timer/rte_timer.h b/lib/librte_timer/rte_timer.h
> > index 4907cf5..35b8719 100644
> > --- a/lib/librte_timer/rte_timer.h
> > +++ b/lib/librte_timer/rte_timer.h
> > @@ -76,7 +76,7 @@ extern "C" {
> >  #define RTE_TIMER_RUNNING 2 /**< State: timer function is running. */
> >  #define RTE_TIMER_CONFIG  3 /**< State: timer is being configured. */
> >
> > -#define RTE_TIMER_NO_OWNER -1 /**< Timer has no owner. */
> > +#define RTE_TIMER_NO_OWNER -2 /**< Timer has no owner. */
> >
> >  /**
> >   * Timer type: Periodic or single (one-shot).
> > @@ -310,7 +310,7 @@ int rte_timer_pending(struct rte_timer *tim);
> >  /**
> >   * Manage the timer list and execute callback functions.
> >   *
> > - * This function must be called periodically from all cores
> > + * This function must be called periodically from EAL lcores
> >   * main_loop(). It browses the list of pending timers and runs all
> >   * timers that are expired.
> >   *
> > --
> > 1.8.1.4



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